1. Field of the Invention
The present invention relates to a ski binding, as well as to a ski provided with such a binding. More specifically, the present invention relates to a binding comprising:
a jaw adapted to receive and retain the front end of a ski boot with respect to a ski. Two lateral wings are provided for this purpose at the rear of jaw. The wings are adapted to grip the boot on both lateral sides thereof;
a support element defining, for the jaw, two frontwardly directed lines of support with respect to the ski, for guiding the lateral pivoting of the jaw. The two lines of support converge upwardly at a point, to define a common plane transverse with respect to the ski, such that lateral pivoting of the jaw with respect to the ski around either one of the lines of support is accompanied by a lifting of the wings of the jaw with respect to the ski; and
an elastic energization mechanism which presses the jaw against the support element and biases the jaw elastically against lateral pivoting around the lines of support.
2. Description of Background and Relevant Information
In bindings of the type described above as well as in the description of the binding of the present which will follow, absent any specific mention to the contrary, the relative positions of the various elements of the ski binding and the ski are understood to be relative to the direction of the normal displacement of these elements.
This type of binding is described in French Pat. Nos. 2,517,214; 2,478,476; 2,458,299; 2,419,737; and 2,420,359 belonging to assignee, which are hereby incorporated by reference.
These types of bindings are adapted to retain the front end of the boot on the ski, while the rear end of the boot is retained on the ski by other means. This front abutment is adapted to free the boot by virtue of lateral pivoting of the jaw when the release threshold of the elastic system is reached, for example, in response to excessive torsional forces on the leg. An appropriate adjustment system is also provided for the elastic energization mechanism which permits adjustment of this release threshold of the elastic mechanism.
Such a simple system responds in a entirely satisfactory fashion to a torsional fall which induces torsional movement of the boot. In such an instance, lateral pivoting of the jaw frees the boot due to lateral pivoting of the retention wings. In addition, lateral pivoting of the jaw can also be accompanied by a frontward movement of the jaw with respect to the support element, against the resistance of the elastic energization.
However, it has been discovered that such a binding is inadequate when a torsional fall is combined with a frontward fall. During a frontward fall, that portion of the sole which is directly beneath the front of the foot is pressed downwardly against the ski with a substantial force, thereby creating an appreciable friction between the sole of the boot and the ski which opposes lateral pivoting of the boot and its liberation from the jaw.
As a result, the bindings described above must include a supplementary apparatus to compensate for this increased friction during a frontward and torsional fall.
For example, it has been proposed to attach a plate composed of materials having a low coefficient of friction to the upper surface of the ski. Such plates can be made, for example, of polytetrafluorethylene or polyethylene, but this type of arrangement has not been entirely satisfactory. Thus, manufacturers have attempted to find other solutions to this problem.
Another solution that has been proposed is to place a sensor beneath the front of the boot. This sensor acts on the elastic energization mechanism so as to reduce the bias against lateral pivoting produced by that elastic mechanism and is described in German Offenlegungschrift No. 2,905,837 or French Pat. No. 2,523,837.
In its French Patents and Certificates of Addition to French Pat. Nos. 83 19397; 84 00346; and 84 03664, the assignee of this application has proposed solutions to this problem which use a plate carrying retention means at the rear end of the boot and which support the sole of the boot. The retention means is journalled on the ski and on the jaw to facilitate a lateral pivoting of the jaw in the event of a torsional fall or in the event a frontward fall is combined with a torsional fall. In French Patent Application No. 86 12910 filed Aug. 17, 1984, the assignee of the present application has also proposed the use of a journalled jaw which is journalled to means for elastically resisting lateral pivoting in a manner so as to facilitate such a pivoting when a torsional fall is combined with a frontward fall. These solutions are more effective than the previously mentioned solutions which relied upon a plate composed of a material having a low coefficient of friction, and are safer than systems utilizing sensors which are vulnerable to freezing and mud and are mechanically susceptible to damage.
It has, however, been observed that the more efficient the means provided to facilitate lateral pivoting in case of a frontward fall the more these means are subject to disturbance by a moment or torque which tends to facilitate this pivoting or on the contrary, to hinder it. This effect results from a pressing of the boot frontwardly on the jaw along a force line which is offset with respect to one or the other of the two support lines of the jaw towards the front around which the jaw pivots with respect to the ski. Thus, these means are particularly sensitive to a frontward force imparted by the boot in the event of a frontward fall.
Therefore, there is a need to prevent the appearance of such a moment or torque, particularly when such means for facilitating lateral pivoting of the jaw are provided, so as to thus ensure more perfect control of the efficiency of these means.